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@article{MZM_1998_64_1_a0, author = {D. N. Azarov}, title = {On the residual nilpotence of free products of free groups with cyclic amalgamation}, journal = {Matemati\v{c}eskie zametki}, pages = {3--8}, publisher = {mathdoc}, volume = {64}, number = {1}, year = {1998}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1998_64_1_a0/} }
D. N. Azarov. On the residual nilpotence of free products of free groups with cyclic amalgamation. Matematičeskie zametki, Tome 64 (1998) no. 1, pp. 3-8. http://geodesic.mathdoc.fr/item/MZM_1998_64_1_a0/